1. Field of the Invention
The present invention relates to a hydraulically operated clutch releasing apparatus, and more particularly, it relates to a self-aligning clutch releasing apparatus in which a clutch releasing bearing and its support are easily disassembled from one another.
2. Related Background Art
In general, clutch releasing apparatuses of this kind include a clutch releasing bearing on a sleeve that is axially slidably mounted on an input shaft protruding from a transmission. Either an inner race or an outer race of the bearing is rotatable, and the rotatable race of the bearing is urged against a torque transmitting member such as a diaphragm spring or a pawl of a clutch device to perform a releasing operation of the clutch.
A self-aligning mechanism may be provided, because it is very difficult to arrange a rotational axis of the clutch releasing bearing and the rotational axis of an associated flywheel along a common straight line, due to differences in accuracy of parts and/or in assembling accuracy. Without a self-aligning mechanism, there is a fair chance of deviation or eccentricity of the rotational axis of the clutch releasing bearing with respect to the rotational axis of the flywheel.
Misalignment of the axes produces an abnormal slip or skidding between the contact surfaces of the torque transmitting member of the clutch device and the clutch releasing bearing. This results in abnormal wear between these contact surfaces, noise, vibration and the like, and deterioration of the clutching operation. Thus, the clutch releasing apparatus develops an uncomfortable feel and has a reduced service life.
Japanese Utility Model Laid-Open No. 61 154329 has proposed a hydraulically operated clutch releasing apparatus wherein a clutch releasing bearing means is mounted on a bearing supporting member with a certain play such that the bearing means can be radially shifted with respect to the bearing supporting member. When the clutch releasing bearing means is rotated while engaging the diaphragm, the bearing means is shifted, by a centripetal force acting on the bearing means, to a position where the rotational axis of the bearing means is aligned with the rotational axis of the flywheel. The aligned clutch releasing bearing means is fixed with respect to the sleeve by a frictional spring force.
In this apparatus, when the clutch releasing operation is completed and then the clutch engaging operation is effected, the case including the bearing means is often rotated around the input shaft of the transmission due to frictional force or vibration acting on the bearing means.
Therefore, when the clutch releasing apparatus is activated again, the aligning operation is also effected again. This increases the wear in the contact portions of the clutch device and the clutch releasing apparatus, thus reducing the service life of the clutch device and/or the clutch releasing apparatus.
Further, when the bearing is to be replaced by a new one (for example, when the bearing has reached its service life after longterm use thereof), since the clutch releasing bearing means is integrally fixed to its supporting means, the whole clutch releasing apparatus must be disassembled. This involves disassembling the and reassembling hydraulic lines supplying the operating oil, and the procedures required are very time consuming.